When plants engage in photosynthesis, sunlight breaks apart water and CO2 to release oxygen and build plant—and people—food. It's cheap and ubiquitous but not much use for powering a home.

Photovoltaic devices use semiconducting material like silicon in a related way, with incoming photons knocking loose electrons to generate electricity. Such devices can produce a lot of electricity on a bright sunny day. Unfortunately, they're too expensive for most folks to afford.

But what if you combined the two? That's exactly what an international consortium of scientists have done, creating a truly green solar cell—and one that can be made from something as common as grass clippings. The findings are in the current issue of Nature: Scientific Reports.

This "electric nanoforest" only produces a trickle of electricity at present, but with refinement it could begin to produce useful amounts of current. Plus, the raw materials are durable and cheap: any living green vegetation will do—nature has seen to that. If such devices can be improved substantially enough, plant-based photovoltaics may finally bring affordable solar power to the remote villages where it's needed most.